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electric charge

positive charge:
- protons (atomic nucleus)
- (kat-) ions (ionized metal, ionized hydrogen, ionized gases... )

negative charge:
- electrons (atomic envelope)
- (an-) ions (remaining acid ions, ...)

force of repulsion between like charges
force of attraction between different charges

elementary charge, charge of an electron

Electricity

Electric charge: a property of some subatomic particles, which determines their electromagnetic interactions. Electrically charged matter is influenced by, and produces, electromagnetic fields.
Electric current: a movement or flow of electrically charged particles, typically measured in amperes.
Electric field: an influence produced by an electric charge on other charges in its vicinity.
Electric potential: the capacity of an electric field to do work on an electric charge, typically measured in volts.
Electromagnetism: a fundamental interaction between the magnetic field and the presence and motion of an electric charge.

voltage source

DC:
cell
battery (3 or more cells in series connection)
accumulator = rechargeable battery or storage battery

AC:
alternating current generator (AC generator)
power supply unit
power transformer
power adaptor

series circuit
series connection


I = constant
U = U1 + U2 + ...
R = R1 + R2 + ...

shunt circuit
parallel circuit
parallel connection

U = constant

I = I1 + I2 + ...

rectification

converter of AC to DC

current
(strength of electric current)

Def.: physival value - means the rate of flow of electric charge through the surface of the conductor (a quantity)
symbol: I
unit: ampère (the rate of one coulomb per second)
symbol: 1 A

voltage
(electrical potential)

Def: physical value (quantity) for galvanic separation
symbol: U
unit: volt
symbol: 1V


(see also: galvanic separation)

resistor (device)
resistance (value)
reluctance (magnetical resistance)
inductance (resistance of an inductor in alternating current = AC)

Def.: physical value, how strong the electric current is restricted
symbol: R
unit:      1 (Ohm)
symbol and basic units:
             
formula:
             

resistivity
(specific electrical resistance or volume resistivity)

Def: measure of how strongly a material opposes the flow of electric current
symbol: ("Rho")

unit:
         
      
or